2-Way Directional Valve (IL)
A two-line flow control valve in an isothermal fluid network.
blockType: EngeeFluids.IsothermalLiquid.Valves.DirectionalControl.TwoWay
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Description
Block 2-Way Directional Valve (IL) It is a two-line valve, for example, a shut-off valve. Use this block to simulate a flow-reducing control element that responds to pressure in another part of the system. The block uses a variable hole to control the flow between ports A and B. The S signal determines the movement of the spool to open or close the valve.
You can parameterize the valve opening linearly or using tabular data.
Linear parameterization
If the value is selected for parameterization Orifice parameterization Linear — Area vs. spool travel, then the area of the passage section of the channel linearly depends on the stroke of the spool and the value coming to the port S:
,
where
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— the position of the spool entering the port S, ;
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— the value of the parameter for moving the spool between the closed and open orifice (the value of the parameter Spool travel between closed and open orifice);
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— leakage area (value of the Leakage area parameter);
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— the value of the parameter of the maximum orifice area (the value of the parameter Maximum orifice area).
Note the linear growth from before in the picture:
When the hole is in an almost open or almost closed position with linear parameterization, you can maintain the numerical stability of the simulation by adjusting the smoothing factor, the value of the Smoothing factor parameter. If the value of the Smoothing factor parameter is not zero, a smooth change in the cross-sectional area between and .
Tabular parameterization
If the value is selected for the parameterization of Orifice parameterization Tabulated data — Area vs. spool travel, the block uses the Spool travel vector and the parameters of the valve area vector to determine the relationship between and by interpolation. and — the first and last elements of the vector of the passage section Opening area vector, respectively.
If the value is selected for parameterization Orifice parameterization Tabulated data — Volumetric flow rate vs. spool travel and pressure drop, then the block uses the volumetric flow rate table Volumetric flow rate table, q(ds,dp), the relative pressure drop vector Pressure drop vector, dp and the spool travel vector Spool travel vector, ds to determine the volumetric flow rate, .
Ports
Entrance
S — position of the spool of the pass distributor:q[<br>] scalar
The inlet port is the position of the distributor spool in m, which defines the area of the valve passage section. A positive value causes the valve to open.
Non-directional
A isothermal fluid port
isothermal liquid
The isothermal fluid port corresponds to the inlet or outlet of the valve. This block has no internal orientation.
B isothermal fluid port
isothermal liquid
The isothermal fluid port corresponds to the inlet or outlet of the valve. This block has no internal orientation.
Parameters
Orifice parameterization — method for calculating the area of the valve
Linear - area vs. spool travel (default) | Tabulated data - Area vs. spool travel | Tabulated data - Volumetric flow rate vs. spool travel and pressure drop
The method of calculating the valve area during modeling.
Spool position at maximum orifice area — spool position at maximum pass area:q[<br>] 5e−3M (default) | positive scalar
The position of the movable spool element when the valve is fully open.
The default value represents a system with zero overlap. A positive non-zero value represents a system with incomplete overlap or a partially closed system. A negative non-zero value represents a shut-off system in which the valve remains open over a range of movements.
Spool travel between closed and open orifice — maximum stroke of the spool
5e−3M (default) | positive scalar
The stroke of the spool between the closed and open states of the valve.
Dependencies
To use this parameter, set the Orifice parameterization parameter to Linear - area vs. spool travel.
Maximum orifice area — maximum cross-sectional area of the pass valve:q[<br>] 1e−4 m2 (default) | positive scalar
The maximum cross-sectional area of the valve during simulation.
Dependencies
To use this parameter, set the Orifice parameterization parameter to Linear - area vs. spool travel.
Leakage area — leakage area through the valve in the fully closed position
1e−10 m2 (default) | positive scalar
The sum of all clearances when the valve is in the fully closed position. Any area less than this value is maintained at the level of the specified leakage area. This parameter contributes to the stability of the numerical solution by maintaining the continuity of the flow.
Dependencies
To use this parameter, set the Orifice parameterization parameter to Linear - area vs. spool travel.
Spool travel vector — vector of positions of the spool
[0, 0.002, 0.004, 0.007, 0.017] m (default) | vector
The position vector of the spool. The dimension of the vector corresponds to the Orifice area vector vector. A positive value corresponds to the valve opening. The values are listed in ascending order, and the first element should be equal to 0. Linear interpolation is used between the data points in the table.
Dependencies
To use this parameter, set the Orifice parameterization parameter to Tabulated data - Area vs. spool travel.
Orifice area vector — vector of values of the area of the passage section of the valve
[1e−09, 2.0352e−07, 4.0736e−05, 0.00011438, 0.00034356] m2 (default) | vector
The vector of values of the valve passage area for tabular parameterization of the valve area. The dimension of the vector corresponds to the Spool travel vector vector. The values are listed in ascending order. The first element is the leakage area, the last element is the maximum cross—sectional area of the channel. Linear interpolation is used between data points.
Dependencies
To use this parameter, set the Orifice parameterization parameter to Tabulated data - Area vs. spool travel.
Spool travel vector, ds — vector of positions of the spool
[0, 0.002, 0.004, 0.007, 0.017] m (default) | vector
A vector of spool positions for tabular parameterization of volume flow. The dimension of the position vector of the spool corresponds to the pressure drop vector Pressure drop vector, dp and the table of volume flow values Volumetric flow rate table, q(ds,dp). The values are listed in ascending order, and the first element should be equal to 0. Linear interpolation is used to calculate the intermediate values.
Dependencies
To use this parameter, set the Orifice parameterization parameter to Tabulated data -Volumetric flow rate vs. spool travel and pressure drop.
Pressure drop vector, dp — vector of differential pressure values
[0.3, 0.5, 0.7] MPa (default) | vector
Vector of differential pressure values for tabular parameterization of volume flow. The dimension of the differential pressure vector corresponds to the position vector of the spool Spool travel vector, ds and the table of volume flow values Volumetric flow rate table, q(ds,dp). The values are listed in ascending order and must be greater. 0. Linear interpolation is used to calculate the intermediate values.
Dependencies
To use this parameter, set the Orifice parameterization parameter to Tabulated data -Volumetric flow rate vs. spool travel and pressure drop.
Volumetric flow rate table, q(ds,dp) — table of pass volume flow values:q[<br>] 1e−3 * [1.7e−05 2e−05 2.6e−05; 0.0035 0.0045 0.0053; 0.7 0.9 1.06; 1.96 2.5 3; 6 7.7 9.13] m3/s (default)` | the m by n matrix
The matrix on volume flow rates corresponding to the values of the differential pressure and the position of the spool. and — the sizes of the corresponding vectors:
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— the number of elements in the spool position vector Spool travel vector, ds.
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— the number of elements in the pressure drop vector Pressure drop vector, dp.
Dependencies
To use this parameter, set the Orifice parameterization parameter to Tabulated data - Volumetric flow rate vs. spool travel and pressure drop.
Discharge coefficient — flow rate
0.64 (default) | a positive scalar in the range [0,1]
The correction factor is the ratio of the actual mass flow to the theoretical mass flow through the distributor.
Dependencies
To use this parameter, set the Orifice parameterization parameter to Linear - area vs. spool travel or Tabulated data - Area vs. spool travel.
Critical Reynolds number — upper limit of the Reynolds number for laminar flow
150 (default) | positive scalar
The upper limit of the Reynolds number for laminar flow through the hole.
Dependencies
To use this parameter, set the Orifice parameterization parameter to Linear - area vs. spool travel or Tabulated data - Area vs. spool travel.
Smoothing factor — numerical smoothing coefficient of
0.01 (default) | a positive scalar in the range [0,1]
The continuous smoothing coefficient, which introduces a level of gradual change based on the flow characteristic when the valve is in the nearly open and nearly closed positions. Set a non-zero value less than one to increase the stability of the simulation in these modes.
Dependencies
To use this parameter, set the Orifice parameterization parameter to Linear - area vs. spool travel.
Pressure recovery — whether to take into account the increase in pressure when expanding the pass area:q[<br>] disabled (by default) | enabled
Should the pressure increase be taken into account when liquid flows from an area with a smaller cross-sectional area to an area with a larger cross-sectional area.
If you uncheck Pressure recovery, this increase in pressure is not taken into account.
Cross-sectional area at ports A and B — area at the inlet or outlet of the pass valve:q[<br>] Inf (default) | positive scalar
The cross-sectional area at the inlet and outlet of the holes A and B. This area is used when calculating the mass flow through the hole.
Dependencies
To use this parameter, set the Orifice parameterization parameter to Linear - area vs. spool travel or Tabulated data - Area vs. spool travel.